1 . 如图,
是半圆
的直径,
是弧
的三等分点,
是线段
的三等分点,若![](https://staticzujuan.xkw.com/quesimg/Upload/formula/434845564fd5765244f8d1aa9240fa39.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/23/c2676fae-59cd-4108-88de-4f8d1b917ba2.png?resizew=156)
(1)求
的值
(2)求
与
的夹角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/39acab3cfb59bfc9591371721ab01d93.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7789a500686c7a73770404ead6af0590.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/434845564fd5765244f8d1aa9240fa39.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/23/c2676fae-59cd-4108-88de-4f8d1b917ba2.png?resizew=156)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf7dcdc182bdc7fab725bbdc01271f69.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d12e6c508b528f9c9c311a6cdf5677b7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe942dc55d43d618d9424849e7f1adc0.png)
您最近一年使用:0次
2020-02-29更新
|
449次组卷
|
2卷引用:上海市宝山区宝山中学2017-2018学年高二上学期10月月考数学试题
名校
2 . 已知平面内n个不同的单位向量
、
、…、![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c9b0d5f1888f4a8de95669bb346d28de.png)
,且n边形
为凸多边形.
(1)当
且
时,求证:三角形
是正三角形;
(2)记![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8fc92bf3b4483312b295837e5c1a678b.png)
,求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f376a1499ca704cd75e784168906d84.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/907d04ad1b2b2895053231d5351ed9e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c9b0d5f1888f4a8de95669bb346d28de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/858560a454ee63031b0a60ee1831a1cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d69385c313b7733f3081e9711a40abef.png)
(1)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be604061cf1591f7069472269d4c9719.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0b09493c8edbcc83b5213bc0104f4cc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56448a74c1b8430c425d79d626764f4f.png)
(2)记
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8fc92bf3b4483312b295837e5c1a678b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/858560a454ee63031b0a60ee1831a1cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad988ed8409a9be8f9c4e4eb91c2e141.png)
您最近一年使用:0次